为什么全WA啊，真的服了，明明在VS和DEV都能通过样例和#1

#include <iostream>
using namespace std;
#include <string>

int calculator(char option, int num1, int num2)
{
    switch(option)
    {
    case '+':
        return num1 + num2;

    case '-':
        return num1 - num2;

    case '*':
        return num1 * num2;
    }
}

string tostring(int x)
{
    if(x == 0) return "0";

    string flag = "";
    if(x < 0)
    {
        flag = "-";
        x = -x;
    }

    string dest = "";
    int digit;
    while(x > 0)
    {
        digit = x % 10;
        x /= 10;
        dest = (char)(digit + '0') + dest;
    }

    dest = flag + dest;

    return dest;
}

string src_to_dest(string src, char& option)
{
    int i = 0;
    int num1 = 0, num2 = 0;
    while(1)
    {
        if('0' <= src[i] && src[i] <= '9') break;

        i++;
    }
    while(1)
    {
        if(!('0' <= src[i] && src[i] <= '9')) break;

        num1 = num1 * 10 + src[i] - '0';
        i++;
    }
    while(1)
    {
        if('0' <= src[i] && src[i] <= '9') break;

        i++;
    }
    while(1)
    {
        if(!('0' <= src[i] && src[i] <= '9')) break;

        num2 = num2 * 10 + src[i] - '0';
        i++;
    }

    if(src[0] == 'a') option = '+';
    else if(src[0] == 'b') option = '-';
    else if(src[0] == 'c') option = '*';

    int result = calculator(option, num1, num2);
    string dest = tostring(num1) + option + tostring(num2) + "=" + tostring(result);
    int size = dest.length();
    dest += "\n" + tostring(size);

    return dest;
}

void test01()
{
    int q;
    cin >> q;
    cin.ignore();
    string src;
    string* dest = new string[q];
    char option = '+';

    for(int i = 0; i < q; i++)
    {
        getline(cin, src);
        dest[i] = src_to_dest(src, option);
    }

    for(int i = 0; i < q; i++)
    {
        cout << dest[i] << endl;
    }

    delete[]dest;
}

void test02()
{
    int q;
    cin >> q;
    cin.ignore();
    string str = "99+999=1098\n11";
    cout << str << endl;
}

int main()
{
    test04();

    return 0;
}